Kinetic Methods

Abstract

In the early fall of 1965 at Arden House, Harriman, N.Y., a score of people were talking about a mysterious serum copper protein, cerulo-plasmin. They were participants in a symposium on copper in biological systems (Peisach et al., 1966). All knew that ceruloplasmin is a copper protein circulating in the bloodstream, having seven or eight copper atoms per protein molecule, with an enzyme activity similar to laccase, but weaker. One said the enzyme activity of ceruloplasmin was just accidental. Others were still trying to find the role of ceruloplasmin (or its contained copper) in a seemingly endless search for physiological activity. Broman (1967) discussed the possible physiological function of ceruloplasmin as a “moot question.” A variety of observations were considered before he suggested that the function of ceruloplasmin is to transfer copper to cytochrome oxidase. Later, catecholamines were proposed as physiological substrates (Walaas, 1967). Then ceruloplasmin was found to be an iron oxidase in serum, and a possible physiological role was identified (Osaki, 1966). Ceruloplasmin is now called ferroxidase (EC 1.16.3.1: Osaki, 1966; Osaki and Walaas, 1967). This is an example of classical steady state kinetic methods revealing one role of an element.